Dear Emiliano,
The molten salt power tower model uses a control flow similar to the one shown in the physical trough reference manual. The diagram in the Wagner 2008 thesis in Figure 57 (p 166) shows the flow control for the power tower model with a two-tank storage system.
Yes. Type 223 is available in the \exelib\transys\source\sam_mw_Type223.f90 file in your SAM installation folder, which, in Windows is in c:\SAM\\ unless you installed SAM in a different folder.
Best regards,
Paul.